Ever-increasing transport of species of all kinds is breaking down biogeographical boundaries with profound consequences for biodiversity loss worldwide (Vitousek et al. 1997, Mooney and Hobbs 2000). When species are transported — intentionally or inadvertently — outside their original geographic ranges, many of them become established and spread. Some proliferate explosively, tending to displace native species in their new area of establishment. Evolving technology (e.g., containers) has increased shipping speeds and volumes, making our detection and interception strategies for stemming the flow of invasives in the United States very difficult to implement and certainly inadequate (Campbell 2001; Loope and Howarth 2003) (fig. 1). Given the seeds of catastrophic loss already planted and those yet to come, invasive species pose a highly significant threat to the biodiversity of the U.S. National Park System in the early decades of the 21st century (e.g., Wilcove et al. 1998). Moreover, global climate change is likely to exacerbate the problem by favoring invasive nonnative species over native species (Mooney and Hobbs 2000). Writing as a former (24 years) employee of the National Park Service, now with the U.S. Geological Survey (USGS), my attempt here is at a personal review and synthesis of implications of trends in biological invasions for national parks, based on personal experience and analyses by others.

Lloyd L. 2004. The challenge of effectively addressing the threat of invasive species to the National Park System. Park Science 22(2):14–20.
Available at http://www.nature.nps.gov/ParkScience/archive/PDF/Article_PDFs/ParkScience22(2)Fall2004_14-20_Loope_2431.pdf.